Warning from headteachers as parents dig deep to fund boom in private tutors

Parents on modest incomes and families from ethnic minorities are behind a massive boom in Britain's multimillion-pound tutoring market, a Guardian investigation can reveal.

Hundreds of thousands of children – some as young as two – now receive private tuition at a cost of between £7 and £60 an hour. Parents say the extra study gives their children confidence and helps them secure top grades, but headteachers are warning that the tutoring market is beginning to spiral out of control and is "trading on insecurity".

Interviews with seven tutoring agencies reveal that:

• One already large tuition business has seen 42% growth over the past year.

• One agency is recruiting 100 new tutors a month to cope with demand.